/*!
* \file soft-se.c
*
* \brief Secure Element software implementation
*
* \copyright Revised BSD License, see section \ref LICENSE.
*
* \code
* ______ _
* / _____) _ | |
* ( (____ _____ ____ _| |_ _____ ____| |__
* \____ \| ___ | (_ _) ___ |/ ___) _ \
* _____) ) ____| | | || |_| ____( (___| | | |
* (______/|_____)_|_|_| \__)_____)\____)_| |_|
* (C)2020 Semtech
*
* ___ _____ _ ___ _ _____ ___ ___ ___ ___
* / __|_ _/_\ / __| |/ / __/ _ \| _ \/ __| __|
* \__ \ | |/ _ \ (__| ' <| _| (_) | / (__| _|
* |___/ |_/_/ \_\___|_|\_\_| \___/|_|_\\___|___|
* embedded.connectivity.solutions===============
*
* \endcode
*
*/
#include <stdlib.h>
#include <stdint.h>
#include "utilities.h"
#include "aes.h"
#include "cmac.h"
#include "LoRaMacHeaderTypes.h"
#include "secure-element.h"
#include "secure-element-nvm.h"
#include "se-identity.h"
#include "soft-se-hal.h"
static SecureElementNvmData_t* SeNvm;
/*
* Local functions
*/
/*
* Gets key item from key list.
*
* \param[IN] keyID - Key identifier
* \param[OUT] keyItem - Key item reference
* \retval - Status of the operation
*/
static SecureElementStatus_t GetKeyByID( KeyIdentifier_t keyID, Key_t** keyItem )
{
for( uint8_t i = 0; i < NUM_OF_KEYS; i++ )
{
if( SeNvm->KeyList[i].KeyID == keyID )
{
*keyItem = &( SeNvm->KeyList[i] );
return SECURE_ELEMENT_SUCCESS;
}
}
return SECURE_ELEMENT_ERROR_INVALID_KEY_ID;
}
/*
* Computes a CMAC of a message using provided initial Bx block
*
* cmac = aes128_cmac(keyID, blocks[i].Buffer)
*
* \param[IN] micBxBuffer - Buffer containing the initial Bx block
* \param[IN] buffer - Data buffer
* \param[IN] size - Data buffer size
* \param[IN] keyID - Key identifier to determine the AES key to be used
* \param[OUT] cmac - Computed cmac
* \retval - Status of the operation
*/
static SecureElementStatus_t ComputeCmac( uint8_t* micBxBuffer, uint8_t* buffer, uint16_t size, KeyIdentifier_t keyID,
uint32_t* cmac )
{
if( ( buffer == NULL ) || ( cmac == NULL ) )
{
return SECURE_ELEMENT_ERROR_NPE;
}
uint8_t Cmac[16];
AES_CMAC_CTX aesCmacCtx[1];
AES_CMAC_Init( aesCmacCtx );
Key_t* keyItem;
SecureElementStatus_t retval = GetKeyByID( keyID, &keyItem );
if( retval == SECURE_ELEMENT_SUCCESS )
{
AES_CMAC_SetKey( aesCmacCtx, keyItem->KeyValue );
if( micBxBuffer != NULL )
{
AES_CMAC_Update( aesCmacCtx, micBxBuffer, 16 );
}
AES_CMAC_Update( aesCmacCtx, buffer, size );
AES_CMAC_Final( Cmac, aesCmacCtx );
// Bring into the required format
*cmac = ( uint32_t )( ( uint32_t ) Cmac[3] << 24 | ( uint32_t ) Cmac[2] << 16 | ( uint32_t ) Cmac[1] << 8 |
( uint32_t ) Cmac[0] );
}
return retval;
}
/*
* API functions
*/
SecureElementStatus_t SecureElementInit( SecureElementNvmData_t* nvm )
{
SecureElementNvmData_t seNvmInit =
{
/*!
* end-device IEEE EUI (big endian)
*
* \remark In this application the value is automatically generated by
* calling BoardGetUniqueId function
*/
.DevEui = LORAWAN_DEVICE_EUI,
/*!
* App/Join server IEEE EUI (big endian)
*/
.JoinEui = LORAWAN_JOIN_EUI,
/*!
* Secure-element pin (big endian)
*/
.Pin = SECURE_ELEMENT_PIN,
/*!
* LoRaWAN key list
*/
.KeyList = SOFT_SE_KEY_LIST
};
if( nvm == NULL )
{
return SECURE_ELEMENT_ERROR_NPE;
}
// Initialize nvm pointer
SeNvm = nvm;
// Initialize data
memcpy1( ( uint8_t* )SeNvm, ( uint8_t* )&seNvmInit, sizeof( seNvmInit ) );
#if !defined( SECURE_ELEMENT_PRE_PROVISIONED )
#if( STATIC_DEVICE_EUI == 0 )
// Get a DevEUI from MCU unique ID
SoftSeHalGetUniqueId( SeNvm->DevEui );
#endif
#endif
return SECURE_ELEMENT_SUCCESS;
}
SecureElementStatus_t SecureElementSetKey( KeyIdentifier_t keyID, uint8_t* key )
{
if( key == NULL )
{
return SECURE_ELEMENT_ERROR_NPE;
}
for( uint8_t i = 0; i < NUM_OF_KEYS; i++ )
{
if( SeNvm->KeyList[i].KeyID == keyID )
{
if( ( keyID == MC_KEY_0 ) || ( keyID == MC_KEY_1 ) || ( keyID == MC_KEY_2 ) || ( keyID == MC_KEY_3 ) )
{ // Decrypt the key if its a Mckey
SecureElementStatus_t retval = SECURE_ELEMENT_ERROR;
uint8_t decryptedKey[16] = { 0 };
retval = SecureElementAesEncrypt( key, 16, MC_KE_KEY, decryptedKey );
memcpy1( SeNvm->KeyList[i].KeyValue, decryptedKey, SE_KEY_SIZE );
return retval;
}
else
{
memcpy1( SeNvm->KeyList[i].KeyValue, key, SE_KEY_SIZE );
return SECURE_ELEMENT_SUCCESS;
}
}
}
return SECURE_ELEMENT_ERROR_INVALID_KEY_ID;
}
SecureElementStatus_t SecureElementComputeAesCmac( uint8_t* micBxBuffer, uint8_t* buffer, uint16_t size,
KeyIdentifier_t keyID, uint32_t* cmac )
{
if( keyID >= LORAMAC_CRYPTO_MULTICAST_KEYS )
{
// Never accept multicast key identifier for cmac computation
return SECURE_ELEMENT_ERROR_INVALID_KEY_ID;
}
return ComputeCmac( micBxBuffer, buffer, size, keyID, cmac );
}
SecureElementStatus_t SecureElementVerifyAesCmac( uint8_t* buffer, uint16_t size, uint32_t expectedCmac,
KeyIdentifier_t keyID )
{
if( buffer == NULL )
{
return SECURE_ELEMENT_ERROR_NPE;
}
SecureElementStatus_t retval = SECURE_ELEMENT_ERROR;
uint32_t compCmac = 0;
retval = ComputeCmac( NULL, buffer, size, keyID, &compCmac );
if( retval != SECURE_ELEMENT_SUCCESS )
{
return retval;
}
if( expectedCmac != compCmac )
{
retval = SECURE_ELEMENT_FAIL_CMAC;
}
return retval;
}
SecureElementStatus_t SecureElementAesEncrypt( uint8_t* buffer, uint16_t size, KeyIdentifier_t keyID,
uint8_t* encBuffer )
{
if( buffer == NULL || encBuffer == NULL )
{
return SECURE_ELEMENT_ERROR_NPE;
}
// Check if the size is divisible by 16,
if( ( size % 16 ) != 0 )
{
return SECURE_ELEMENT_ERROR_BUF_SIZE;
}
aes_context aesContext;
memset1( aesContext.ksch, '\0', 240 );
Key_t* pItem;
SecureElementStatus_t retval = GetKeyByID( keyID, &pItem );
if( retval == SECURE_ELEMENT_SUCCESS )
{
aes_set_key( pItem->KeyValue, 16, &aesContext );
uint8_t block = 0;
while( size != 0 )
{
aes_encrypt( &buffer[block], &encBuffer[block], &aesContext );
block = block + 16;
size = size - 16;
}
}
return retval;
}
SecureElementStatus_t SecureElementDeriveAndStoreKey( uint8_t* input, KeyIdentifier_t rootKeyID,
KeyIdentifier_t targetKeyID )
{
if( input == NULL )
{
return SECURE_ELEMENT_ERROR_NPE;
}
SecureElementStatus_t retval = SECURE_ELEMENT_ERROR;
uint8_t key[16] = { 0 };
// In case of MC_KE_KEY, only McRootKey can be used as root key
if( targetKeyID == MC_KE_KEY )
{
if( rootKeyID != MC_ROOT_KEY )
{
return SECURE_ELEMENT_ERROR_INVALID_KEY_ID;
}
}
// Derive key
retval = SecureElementAesEncrypt( input, 16, rootKeyID, key );
if( retval != SECURE_ELEMENT_SUCCESS )
{
return retval;
}
// Store key
retval = SecureElementSetKey( targetKeyID, key );
if( retval != SECURE_ELEMENT_SUCCESS )
{
return retval;
}
return SECURE_ELEMENT_SUCCESS;
}
SecureElementStatus_t SecureElementProcessJoinAccept( JoinReqIdentifier_t joinReqType, uint8_t* joinEui,
uint16_t devNonce, uint8_t* encJoinAccept,
uint8_t encJoinAcceptSize, uint8_t* decJoinAccept,
uint8_t* versionMinor )
{
if( ( encJoinAccept == NULL ) || ( decJoinAccept == NULL ) || ( versionMinor == NULL ) )
{
return SECURE_ELEMENT_ERROR_NPE;
}
// Check that frame size isn't bigger than a JoinAccept with CFList size
if( encJoinAcceptSize > LORAMAC_JOIN_ACCEPT_FRAME_MAX_SIZE )
{
return SECURE_ELEMENT_ERROR_BUF_SIZE;
}
// Determine decryption key
KeyIdentifier_t encKeyID = NWK_KEY;
if( joinReqType != JOIN_REQ )
{
encKeyID = J_S_ENC_KEY;
}
memcpy1( decJoinAccept, encJoinAccept, encJoinAcceptSize );
// Decrypt JoinAccept, skip MHDR
if( SecureElementAesEncrypt( encJoinAccept + LORAMAC_MHDR_FIELD_SIZE, encJoinAcceptSize - LORAMAC_MHDR_FIELD_SIZE,
encKeyID, decJoinAccept + LORAMAC_MHDR_FIELD_SIZE ) != SECURE_ELEMENT_SUCCESS )
{
return SECURE_ELEMENT_FAIL_ENCRYPT;
}
*versionMinor = ( ( decJoinAccept[11] & 0x80 ) == 0x80 ) ? 1 : 0;
uint32_t mic = 0;
mic = ( ( uint32_t ) decJoinAccept[encJoinAcceptSize - LORAMAC_MIC_FIELD_SIZE] << 0 );
mic |= ( ( uint32_t ) decJoinAccept[encJoinAcceptSize - LORAMAC_MIC_FIELD_SIZE + 1] << 8 );
mic |= ( ( uint32_t ) decJoinAccept[encJoinAcceptSize - LORAMAC_MIC_FIELD_SIZE + 2] << 16 );
mic |= ( ( uint32_t ) decJoinAccept[encJoinAcceptSize - LORAMAC_MIC_FIELD_SIZE + 3] << 24 );
// - Header buffer to be used for MIC computation
// - LoRaWAN 1.0.x : micHeader = [MHDR(1)]
// - LoRaWAN 1.1.x : micHeader = [JoinReqType(1), JoinEUI(8), DevNonce(2), MHDR(1)]
// Verify mic
if( *versionMinor == 0 )
{
// For LoRaWAN 1.0.x
// cmac = aes128_cmac(NwkKey, MHDR | JoinNonce | NetID | DevAddr | DLSettings | RxDelay | CFList |
// CFListType)
if( SecureElementVerifyAesCmac( decJoinAccept, ( encJoinAcceptSize - LORAMAC_MIC_FIELD_SIZE ), mic, NWK_KEY ) !=
SECURE_ELEMENT_SUCCESS )
{
return SECURE_ELEMENT_FAIL_CMAC;
}
}
#if( USE_LRWAN_1_1_X_CRYPTO == 1 )
else if( *versionMinor == 1 )
{
uint8_t micHeader11[JOIN_ACCEPT_MIC_COMPUTATION_OFFSET] = { 0 };
uint16_t bufItr = 0;
micHeader11[bufItr++] = ( uint8_t ) joinReqType;
memcpyr( micHeader11 + bufItr, joinEui, LORAMAC_JOIN_EUI_FIELD_SIZE );
bufItr += LORAMAC_JOIN_EUI_FIELD_SIZE;
micHeader11[bufItr++] = devNonce & 0xFF;
micHeader11[bufItr++] = ( devNonce >> 8 ) & 0xFF;
// For LoRaWAN 1.1.x and later:
// cmac = aes128_cmac(JSIntKey, JoinReqType | JoinEUI | DevNonce | MHDR | JoinNonce | NetID | DevAddr |
// DLSettings | RxDelay | CFList | CFListType)
// Prepare the msg for integrity check (adding JoinReqType, JoinEUI and DevNonce)
uint8_t localBuffer[LORAMAC_JOIN_ACCEPT_FRAME_MAX_SIZE + JOIN_ACCEPT_MIC_COMPUTATION_OFFSET] = { 0 };
memcpy1( localBuffer, micHeader11, JOIN_ACCEPT_MIC_COMPUTATION_OFFSET );
memcpy1( localBuffer + JOIN_ACCEPT_MIC_COMPUTATION_OFFSET - 1, decJoinAccept, encJoinAcceptSize );
if( SecureElementVerifyAesCmac( localBuffer,
encJoinAcceptSize + JOIN_ACCEPT_MIC_COMPUTATION_OFFSET -
LORAMAC_MHDR_FIELD_SIZE - LORAMAC_MIC_FIELD_SIZE,
mic, J_S_INT_KEY ) != SECURE_ELEMENT_SUCCESS )
{
return SECURE_ELEMENT_FAIL_CMAC;
}
}
#endif
else
{
return SECURE_ELEMENT_ERROR_INVALID_LORAWAM_SPEC_VERSION;
}
return SECURE_ELEMENT_SUCCESS;
}
SecureElementStatus_t SecureElementSetDevEui( uint8_t* devEui )
{
if( devEui == NULL )
{
return SECURE_ELEMENT_ERROR_NPE;
}
memcpy1( SeNvm->DevEui, devEui, SE_EUI_SIZE );
return SECURE_ELEMENT_SUCCESS;
}
uint8_t* SecureElementGetDevEui( void )
{
return SeNvm->DevEui;
}
SecureElementStatus_t SecureElementSetJoinEui( uint8_t* joinEui )
{
if( joinEui == NULL )
{
return SECURE_ELEMENT_ERROR_NPE;
}
memcpy1( SeNvm->JoinEui, joinEui, SE_EUI_SIZE );
return SECURE_ELEMENT_SUCCESS;
}
uint8_t* SecureElementGetJoinEui( void )
{
return SeNvm->JoinEui;
}
SecureElementStatus_t SecureElementSetPin( uint8_t* pin )
{
if( pin == NULL )
{
return SECURE_ELEMENT_ERROR_NPE;
}
memcpy1( SeNvm->Pin, pin, SE_PIN_SIZE );
return SECURE_ELEMENT_SUCCESS;
}
uint8_t* SecureElementGetPin( void )
{
return SeNvm->Pin;
}